Variable pitch propeller blade root construction



F. TO'RNES ETAL 2,612,229

Sept. 30,195;

J VARIABLE PITCH PROPELLERTBLADE ROOT CONSTRUCTION Filed March 15, 1946 I IA/warren :95 M Y- ".8 2

B M m Patented Sept. 30, 1952 :3.

,- vARiABLnPrrGHnnorErm RinLAnniithoi" goonernucrrorr Ferdlhand Tornes and Nils JohannesLiaaem 'Aalesundz,,;Nomay;

Assessin- Marchit, 1946;.SerialNo. 654.752. I j If1 Marclr.6, ,'1945f,

' 3 Glaims The present invention "relates to- 'aQhub' construction for ship propell'ersand 'turbin" with turnable 'bl'ades which can-"be turned--wh'enin operation.

It i1=, -li-hown in propellers and 'turbin'eswith turnable bl'ades" to secure the blades by screw bolts in the blade root to a 'turnable disc (crank disc) inside the hub, by means of which the blade is turned. In a known construction a flange on this disc forms,.toge'ther witha radial. face-on the blade root a circular grooveinthe. fastening. end of the blade. In this groove a ring is provided which by means of screws in its outer edge is 01. nee-1.6mm-

crank disc t is provided with a; meezwhi-ehfrestsz secured to the hub and whiclritakes up the centriiugal" force and the bending moment on the blade. In. this construction: the disc is. first. inserted radially in the hub. whereafter theirin'g whichv partly covers the discyisg'sscrewed jfto the hub and the: bladescrewedtothe-disc.

It has' also been suggested. tosecure theblade by means of screw bolts in the root of the blade to an outer disc and an inner crank disc, coming to rest one on each side of a ring made in one piece with the hub, the inner disc being made in several parts of such dimensions that they can be passed centrally through the opening of the ring and thereafter assembled and screwed to the blade root.

According to the present invention the hub and the crank disc are made so that the crank disc can be passed in one piece into the hub,- axially through an opening in the end of the same, and that it comes to rest against a bearing face made in one piece with the hub. The construction thus becomes simpler, cheaper and stronger than the known constructions, and the mounting of the blade also becomes simpler.

The drawing illustrates an example of an embodiment of a propeller according to the invention. Fig. 1 is a longitudinal section through hub and blade root and Fig. 2 is partly a transverse section through the same and partly a viewof the hub from behind with the aft cover removed.

The propeller shaft l is connected to the hub 2 by means of a flange, the hub being provided with a ring 3 for each blade, the ring having two faces 3a and 3b at right angles to the axis of the blade, and a face 3c which is cylindrical about the axis of the blade. The root of propeller blade 4 is formed so that it seats with a running fit against the faces 3a and 30 on the hub 2. A sealing ring 4a is inserted between the blade and the hub. To the blade 4 is secured, by means of the screw bolts 6,a crank disc 5 which is further secured against rotation by means of the pins 1. The

- opening i9 in; its .endeu icie fly l e-to allow;

the. crank disc :5. tobe passed axiallyintogthe; 11 1band installed in place; resting-against the face 31 inthe samer The opening l9 is-closedby means. of the cover 2!! which is secured by thes'seiew' bolts-2d; 1

The propeller blades are fitted in the following way.

The hub is secured to the shaft l in which the rod I8 is inserted, and the rod i3 is connected to this rod.- The discs 5 are brought in place and the blades 4 secured by means of the screw bolts 6 and the pins 1. When all blades are fitted in this way the blades are swung so that the pins 8 on the discs are in the center line of the blade p 't the p ning 19. The part H] of the connecting-link thereafter is slid axially in on the rod I3, a groove Illa being provided for the pin 8. The blades 4 then are swung so that the pin 8 is moved somewhat sideways to the rod l3, thereby giving room for sliding the nuts 9 on the pins 8. These nuts are kept in place by the part II of the connecting-link when the same is slid on the rod l3, this part having a face Ila against which the nut 9 can rest. The last part H. of the connecting-link is slid on the rod l3 and the whole connecting-link secured to the rod by means of the screw nut M. For further securing of the parts together the screw bolts l5 are inserted. Finally, the cover 20 is secured by means of the screw bolts 21.

If the hub is made with suiflciently large diameter the connecting-link may be made as one unit. The connecting-link pre-assembled with nuts and crank discs then may be inserted through an opening of the necessary size in the end of the hub. For propellers with two blades this can be donewithout increasing of the diameter of the hub.

propeller shaft this movement is by means of the connecting-link converted into a turning of the several blades about their respectve axes,

a hollow hub, a plurality of blades mounted radially therein, and means operatively connected to the inner ends of said blades for turning said blades about their axes, each said blade having an annular flange adjacent its root end,

, said hub having a radial opening for each blade,

the -periphery of each "said opening .having a flange providing a seatfor. the flange of said blade root, and said turning means comprising acrank disc secured to said blade root and seatv ing upon the inner surface of said hub flange,

said hub having an axial opening of a diameter groove for a bearing ring in ,the hub, the COII-L nection between the blade andthe crank disc being established by means of screw bolts extending through the said flange at the root end of the blade and screwed into the said crank disc, saidhub' having an axial opening of a diameter sufficient to permit passage-of said crankdiscs into the interior of said hub, said flange and said'crank disc bearing against the outer and inner surfaces respectively of a bearing ring made integral -with the hub in the wall of the same. '12. In an adjustable pitch propeller as defined in'claim 1 a blade-turning means comprising a member movable axially-of said hub, a crank pinon' each of said crank discs, and means operatively connecting said member and said pins, this means comprising a nut on each said crank pin, three parts slidable longitudinally onto said member, two of said parts being spaced apart by said third part and being adapted to accommodate therebetween the said nuts on said crank pins, and means for securing said parts together and for securing the same in place on said member.

3. In an adjustable pitch propeller or the like,

suificient to permit passage of said crank discs into the interior of said hub, said blade-turning means comprising a member movable axially of said hub, a crank pin on each of said crank discs, and means operatively connecting said member and said pins, said last means comprising a nut on each said crank pin, three parts slidable longitudinally onto said member, two of said parts being spaced apart by said third part and being adapted to, accommodate therebetween the said nuts on said crank pins, and means for securing said parts together and for securing the same in place on said member. w FERDINAND TORNES.

NILS JOHANNES LIAAEN.

REFERENCES CITED ihe following references. are of record in the,

file of this patent: I

UNITED STATES PATENTS 

